<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title>Document</title>
</head>

<body>
    <button id="btn">发送请求</button>
    <div id="container"></div>
    <script type="text/javascript">
        var btn = document.getElementById('btn');
        var container = document.getElementById('container');

        btn.onclick = function() {
            var xhr = new XMLHttpRequest();
            xhr.open('get', '/xml');
            xhr.send();
            xhr.onload = function() {
                // xhr.responseXML 获取服务器端返回的xml数据
                var xmlDocument = xhr.responseXML;
                var title = xmlDocument.getElementsByTagName('title')[0].innerHTML;
                container.innerHTML = title;
            }
        }
    </script>
</body>

</html>